There are a number of situations where people become separated from a motor vehicle and desire to find it in a simple and expeditious manner. One such example are quail hunters who ride in a truck following bird dogs working on the ground in a brushy area where visibility is perhaps thirty yards. When the dogs locate quail, the hunters leave the truck and run after the dogs. In a typical hunting episode, the hunter leaves the vehicle, follows the dogs for five minutes or so and shoots a bird or two. When the hunter catches his breath and looks around, he often cannot see the vehicle. In one of those oddities of life, dogs are trained to find birds but are not trained to find trucks. Because the hunter is running after the dogs, the hunter often loses a sense of direction and cannot find the truck.
There are two known systems to help a hunter find a truck in an area of restricted visibility. Satellite based ground systems operate by using a receiver carried by the hunter. Before leaving the vehicle, the receiver is manipulated and the position of the truck is recorded. When the hunter desires to return to the vehicle, the receiver is manipulated to determine the route to the original position. These systems are expensive and require the use to manipulate the receiver before leaving the truck to establish the truck's position. In the excitement of a hunt, this is not likely to be done every time so even the most sophisticated available equipment has serious disadvantages.
Coon hunters use a radio transmitter attached to a dog's collar and a receiver carried by the hunter so the hunter can follow the dog. A similar transmitter can be placed in the truck and operates to guide the hunter back to the truck if the hunter remembers to turn it on before leaving. In the excitement of a hunt, this is not likely to be done every time so even radio tracking equipment has serious disadvantages.
Of some interest relative to this invention are U.S. Pat. Nos. 2,477,857; 4,129,857; 4,305,062; 4,797,671; 4,933,664 and 5,278,556.